Environmental Impact Inputs

The outline of the environmental impact methodology is found in Section 3.3.4. In order to capture the impact of deicers post-application, the number of chemical elements added to the environment is calculated. This is calculated using the molar weights of each chemical element and the percentage of deicer molecule that is comprised of an individual chemical element. These percentages were used to determine the amount of the deicer that is comprised of a specific chemical element. The elements considered in this research from the four deicers are Ca, Cl, Mg, and Na.

Biological Matter, while not an individual element, was also considered in order to holistically capture the end of life effects from OBPE Deicer. Biological Matter and Acetate were considered as a whole and not as individual elements because their greatest impacts would be in this condition whereas with the other deicers, greatest impact comes from addition of certain

elements directly to the environment. The H2O molecules that are found in the CaCl2 Deicer

were not considered because H2O is not considered to be an element of concern and would have

a neutral impact on the surrounding environment. The total amounts of each element present for each deicer is included in Table 12.

Table 12: Element Quantities Per Deicer

Based upon the available literature and known threats of deicers to water and soil, five factors were be considered and weighted: D.O., TDS, Heavy Metal Leaching, Human Health, and Aquatic Health. The impacts of these factors to the environment are discussed in Sections 2.2 and 6.2. Each factor is provided a weight based upon the severity of impacts from that factor. For the purpose of this research a simple 1-5 weighting scale was used. This scale was selected because it decreases the relative difference between a least impactful and most impactful factor.

Any scale can be chosen as long as it accurately represents the difference in impacts post- application. The results from this model will be relative to one another, but by varying the weighting scale the difference in impact of each deicer will vary.

As discussed in Section 3.3.4, the factors chosen and their associated weights should be based upon a review of the literature. The goal is to accurately capture the potential ways in which a product may impact the environment post-application. While there is some discretion required in the selection and weighting process, thorough literature review, research, and analysis should provide substantive rationale behind all inputs.

Upon determining weights and factors, all chemical components (Ca, Cl, Mg, Na, Acetate, and Biological Matter) associated with the deicers will be marked as either “yes” or “no” to having direct associated changes with one of the five factors. If an element is marked as “yes” to having a direct association with one of the environmental factors, the assigned weight of that environmental factor is added together with all other impairment factor weights that were marked “yes.” The sum of all weights is then multiplied by the total quantity of the chemical component present. Chemical component quantities will vary from each deicer. For the purpose of this research, this final number is called the Environmental Impact Score. An Environmental Impact Score can be assigned to each deicer based upon its chemical composition of these elements.

The terminology and methodology for creating an Environmental Impact Score is unique to this research and cannot be directly compared to any other metric or impact score that is not included in this model. This research serves as a first-time case study for this model, which has been developed to capture effects of deicing post-application and compare the results with standard lifecycle analysis results from SimaPro 8.

In Table 13 the weights and Total Impairment Scores for each chemical component are given. As discussed, the weights were based on a 1-5 scale. This scale was chosen in order to show the differences in severity of each factor without over-inflating differences between factors. A weight of one was considered to represent minute impact, two represents some impact, three

represents noticeable impacts, four represents impact of concern, and five represents impact of great concern.

Table 13: Impairment Weighting and Scores

Ion balances retrieved from (Environmental Protection Agency Lake Access, n.d.)

The ion balance in typical fresh water for the cations and anions are provided to give a basic understanding of the presence of certain materials in the environment when it is relatively undisturbed (Environmental Protection Agency Lake Access, n.d.). TDS was given the lowest weighted score of 2, because the impacts from these dissolved solids are not inherently linked to negative environmental impacts. TDS is a good indicator of specific conductivity and may also be linked to an increased need to filter water. TDS alone, though, serves more as a measure of clarity than necessarily poor environmental quality (USGS n.d.a).

D.O. was given a score of 3 because it does directly impact environmental quality. Decreases in D.O. impact biodiversity because aquatic life can be sensitive to oxygen levels. At its most severe, eutrophication can occur (USGS, n.d.a). Heavy metal leaching was also given a value of 3 because the presence of heavy metals in the environment impacts soil and water quality as well as the ability to life to grow. In some cases heavy metals, once present in the environment, are extremely difficult to remove (Kluge, Werkenthin, & Wessolek, 2014).

Finally, aquatic and human health were assigned values of 4 and 5 respectively. An element was determined to be directly correlated with aquatic health or human health if there is a corresponding standard set for that elements presence in the environment. A standard set by the EPA implies there have been or continue to be issue, or that impacts to aquatic health or environmental health can be extensive. Aquatic health was assigned a 4 and human health was assigned a 5 because human health is often prioritized. (New Hampshire Department of Environmental Services, 2016)

Direct association of an element with one of the five factors was based upon information from government resources such as the EPA and USGS, as well as from readily available scientific literature (USGS, n.d.a; New Hampshire Department of Environmental Services, 2016; Bang and Johnston, 1998; Warner, 2016; USGS, 2014; Brener and Horner, 1992; Siegel, 2007).